SAN DIEGO -- The San Diego Chargers announced last week that team doctor David Chao was quitting to spend more time with his family and to nurse his ailing back. But records obtained by USA TODAY Sports claim that another factor led to the controversial doctor's resignation.

Two San Diego hospitals decided not to allow Chao to perform surgeries there anymore -- a move that recently was finalized and jeopardized his job with the team, according to a signed declaration submitted in San Diego Superior Court this week.

In recent years, officials at Scripps Memorial Hospital and Scripps Mercy Hospital in San Diego conducted reviews of Chao's quality of care and of his alcohol consumption, according to hospital letters obtained by USA TODAY Sports. Several former patients of Chao's also had accused him of maiming them during surgeries or negligence, including one case that led Scripps Memorial Hospital to settle for $1.39 million.

"Following an investigation of Dr. Chao undertaken jointly at Scripps Memorial Hospital, La Jolla and Scripps Mercy Hospital, the Medical Executive Committees at the Hospitals recommended the revocation of Dr. Chao's medical staff membership and privileges," Scripps said in a statement released Thursday to USA TODAY Sports.

After the vote to revoke, Chao asked for a hearing as the hospitals filed a notice of charges against him, the hospitals said. The case was recently settled with Chao agreeing to call off the hearing and to not seek reappointment with the hospitals. No formal findings were made because the hearing never took place. The hospitals declined further comment.

Attorney Marc Stern, a longtime legal opponent of Chao's, said the hospitals' decision jeopardized Chao's practice and job with the Chargers. He said members of Chao's surgery center are required to be members of an accredited acute-care hospital nearby, according to the surgery center's bylaws. Stern made his statements in a declaration submitted to the court this week in relation to a lawsuit against Chao.

"This has led, apparently, to Dr. Chao resigning his position with the Chargers," Stern wrote in the declaration, which was made under the penalty of perjury. "This will also inevitably lead to the closure of … Dr. Chao's surgical practice."

The Chargers declined comment.

Chao's attorney Robert Frank disputed Chao's loss of hospital privileges all week, saying it was all false. On Tuesday, he pointed out that Chao still had a bio page on the Scripps website. However, on Wednesday that page was no longer active and Chao was not listed among Scripps doctors. Frank also said the hospital situation is not the reason Chao quit.

The loss of privileges at Scripps restricts his ability to perform surgeries there. This skill – performing surgeries -- is his calling card as an NFL team doctor and at his private surgical facility, Oasis. "We are the team physicians for the San Diego Chargers and you!" says a poster that greeted visitors at Oasis this week.

Frank said that "not having privileges at Scripps didn't restrict his ability to do surgery at surgery centers, including the Oasis facility."

Such a revocation or suspension of privileges often happens when a hospital's governing committee decides the doctor is no longer qualified to work there or has failed to meet proper standards.

Frank denied Stern's statement that the hospital situation is connected to Chao's resignation. He said Chao doesn't perform player surgeries at Scripps.

In his declaration, Stern said that the hospital decision still would affect Chao's ability to perform surgeries even at his own surgery center.

In a statement released by the Chargers last week, Chao gave a different reason for his resignation. "I talked to the Chargers about my back problems in March and my desire to spend more time with my newborn twins and young daughter," Chao said in the statement. He also said he could no longer continue his work with the X Games or USA Rugby.

In recent years, Chao has been besieged by legal problems and criticism from the NFL players union, although several current and former Charger players have vouched for him.